Mechanism for converting rotary movement into reciprocatory movement



June 1960 s. R. mas 2,942,484

MECHANISM FOR CONVERTING ROTARY MOVEMENT INTO RECIPROCATORY MOVEMENT Filed Feb. 19, 1959 3 Sheets-Sheet 1 L i. la

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June 28, 1960 G. R. DIBB 2,942,484

MECHANISM FOR CONVERTING ROTARY MOVEMENT INTO RECIPROCATORY MOVEMENT 3 Sheets-Sheet 2 Filed Feb. 19, 1959 -4- 13a I)? 14a l 15 b 9 I E $4312 Fbg i H 45 MWEAWDQ saei E ZNBB June 28, 1960 2,942,484

(1 R.IJ"3E MECHANISM FOR CONVERTING ROTARY MOVEMENT INTO RECIPROCATORY MOVEMENT Filed Feb. l9, 1959 3 Sheets-Sheet 3 MECHANISM FOR CONVERTING ROTARY MOVE- MENT INTO RECIPROCATORY MOVEMENT George Robert Dibb, Sarana, 106 Cheyne Walk, Chelsea,

London, SW. 10, England Filed Feb. 19, 1959, Ser. No. 794,287 Claims priority, application Great Britain Feb. 21, 1958 2 Claims. (or. 14-40 for actuating a reciprocatory plunger of a pump, more especially, although not eseentially, a fuel injection pump forinternal combustion engines, it may advantageously be used for any other purpose where it is necessary to drive a reciprocatory member from a source of rotary motion. One suitable alternative use to which the mechanism can be put is for actuating a vibratory apparatus such as is used for carrying out metal fatigue tests in workshops in which a supporting platform is subjected to vibration by one or more reciprocatory members. Another use to which the mechanism of this invention may be put is for actuating a pawl for turning a ratchet wheel effecting feed movement of tool slides, machine tables and so on.

l The main object of the invention is to provide mechanism for the purpose referred to which permits the stroke of the reciprocatory member to be varied infinitely between zero and a predetermined maximum.

A further object of the invention is to provide mechanism in which the variation of the stroke of the reciprocatory member can be effected automatically by means which is responsive to changes in the speed of the rotary member. Thus, in the case where the reciprocatory member is a plunger of a fuel pump, then the mechanism can be driven from a suitable part of the engine and the stroke of the plunger varied to suit different Working conditions of the engine.

Another object of the invention, as applied. to a liquid fuel injector pump, is to provide an arrangement in which the pump is self-priming whereby vapour lock in the pump, due to temperature rise during an idle period after use, is eliminated. I, I 7

A still further object of the invention is to provide mechanism for the purpose referred to which is simple and inexpensive to make and which lends itself readily 'to mass production methods.

Still another object of the invention is to provide mechanism for the purpose referred to whichis capable of being adjusted either manually or automatically while the parts are in operation.

Broadly, according to the present invention, there is provided mechanism for the purpose referred to which comprises a rocker arm or cross head pivoted between its ends to a member to be reciprocated, an eccentric,

crank, cam or the equivalent connected to or adapted to engage said rocker arm at each side of its pivot, the eccentrics being adapted to act'respectiveiy on opposite sides of the rocker arm so as to move the latter bodily to reciprocate the said member when the eccentrics are wholly or partly in phase, means being provided for driving said eccentrics or the like and means for infinitely adjusting the eccentrics relatively to one another, or one relatively to the other, through a range of partly, out-.ofphase positions to vary the bodily displacement of the r ICC pivotal axis of the rocker arm and therefore the stroke Figure 2 is 'a fragmentary sectional view drawn toa larger scale of the lower end of one, of the pump pistons. Figure 3 is a vertical section of the pump taken in a plane at rightangles to Figure l and on the line III-III of Figure 4.

I Figure 4 isa projected section taken on the line IVIV ofFigure-l. I

Figures 5 to.7 are purely diagrammatic views illustrating the setting of the eccentrics when they (a) are whollyout of phase ;and impart no stroke to. the'piston or plunger, (1)) are only partly out of phase and set to produce'approximately a half strokeof the piston, and (c) ,are completely in phase to produce full stroke of the piston, and i v a Figure8 is an explanatory diagram illustrating the relation between the parts for obtaining the settings shown in Figures 5 to 7. f The pump illustrated in,the drawings is intended .for use with a four cylinder engine and for this reason comprises four pistons..which pump fuel to four injectors associated one Witheach, of the engine cylindersx The pumpmay of course comprise only one piston or more or'less than four pistons to suit requirements.

Refer'ringtov the drawings, the pump comprises four elongated'tubular pistons'or plungers 1 each arranged with its axis disposed'vertically and with its upper and lower ends slidably supported in bores in spaced. apart portions 2 and 3 of a' main body part 4so as to. leave anint'ermediate part of the tubular plunger free'for: en-

g'agement by means described in detail hereinafter for imparting a reciprocatory movement tolthe plunger 1 in such a manner that the lengths of stroke can be varied infinitely between zero and a predetermined maximum;

1 is connected by way of a chamber 7 to a fuel inlet 8 and, during downward movement of the plunger 1, the

fuel enters the enlarged diameter lower end-5 thereof 'by a way. of the ball valve 6 which it lifts off its seating 6b, the-valve 6 being forced against its seating 6b so as 'to close the lower end of the plunger 1 when the latter rises during its fuel injection stroke when fuel-is discharged through the upper end 1a to a pipe (not shown) connected to an outlet 9 and thence to a fuel injector nozzle associated with a cylinder of the engine.

The enlarged diameter lower end 5 of the plunger 1 constitutes a pumping chamber and also a priming chamber which renders the pump selfpriming and also acts to eliminate vapour lock due to temperature rise during an idle period after use.

"If desired, a suitable non-return valve may be inserted adjacent to the, upper end of the plunger inthe'fuel line leadlng'touhe fuel injector nozzle of the cylinder supplied by the particular plunger. 1 I

The guiding of the ends of eachtubular plunger 1 in co-axial bores in the. portions 2 and 3 of -the mainJbodypart ensures alignment and, if necessary, thesetendsf'df the plunger may slide through any-suitable glands (not illustrated).

The means forimparting an infinitely variable Patented June 28,

catory movement to each plunger 1 comprises a rocker member or the equivalent pivoted between its ends at 11 to the plunger 1 and which is pivotally engaged at each side of its pivot at 12a by the straps 12 of eccentrics or earns 13 and 13a disposed at opposite sides of the rocker member, i.e. one above and one below and which are carried by shafts 14 and 14a in such a manner that the eccentrics 13 and 13a act on the rocker member 10 (when the eccentrics are wholly or partly in phase) to move the latter bodily to displace the plunger 1 axially to effect a pumping stroke. The said eccentrics are inter-connected by means for turning one or both of them so that they can be infinitely adjusted relatively to one another, or one relatively to the other, through a range of partly out-of-phase positions to vary the movement or stroke of the rocker member 10 at the point 11 Where it is pivotally connected to the plunger 1. In the specific embodiment being described, the shaft 14 is driven by the engine of which the pump forms a part and due to the resistance of the driving connection thereto can be regarded as non-adjustable for the purpose of setting the eccentric 13 carried thereby and for this reason the eccentric 13a on the shaft 14a is the one which is adjusted to vary the relative setting of the two eccentrics and therefore the stroke of the plunger 1, the setting of the eccentric 13 remaining constant.

The two shafts 14 and 14a are interconnected by a train of five or any other suitable number of gears 15 which are constantly driven by the engine through the shaft 14 carrying the eccentric 13 so that the gear on the shaft 14a always drives the latter and therefore the eccentric 13a carried thereby. The arrangement is substantially the same when both shafts 14 and 14a are free to be turned for adjustmentof the eccentrics in which case the eccentrics 13 and 13a are turned simultaneously in opposite directions and are advanced and retarded relatively to one another. The eccentrics are preferably circular as shown but may be cam-shaped if desired.

The two end gears 15 of the train of gears are fixedly secured to their respective shafts 14 and 14a and the remaining three intermediate gears are supported by a bodily displaceable link 16 (see particularly Figures 4 to 7) which is pivoted at its ends to arms 17 and 18 which are mounted loosely .on the shafts 14 and 14a respectively. Thus, by swinging the arm 18 by turning a squared portion 19 extending from this arm (see Figure 4) the three arms 16, 17 and Bean be caused to assume an infinite number of different angular positions (three of which are illustrated inFiguresS, 6 and7). It is to be emphasised that Figures 5 to 7 are purely diagrammatic and that the shafts 14 and 14a have been purposely extended to space the linkage away from the first set of eccentrics and their rocker member, to which they are normally closely disposed as shown in Figures 3 and 4, so that the action of the linkage and gears .can be clearly illustrated. When adjusting said arms the gears 15 are caused to turn as they are always in mesh and drive back on to the gear which is fitted to the shaft 14a so as to advance or retard this shaft and the eccentric 13a carried thereby. This adjustment can be made when the gears 15 are in motion with both shafts 14 and 14a rotating to drive their respective eccentrics 13 and 13a.

In Figure 5 the eccentrics 13 and 13a are 180 out of phase and cause the rocker arm 10 simply to rock about its pivot 11 Without displacing the rocker member bodily with the result that no stroke is imparted to the piston 1. In Figure 6 the eccentric 13a has been moved 90 out of phase with the other eccentric 13 with the result that the rocker member is displaced bodily as indicated in chain-dotted outline so that the plunger is moved approximately half its stroke.

When the eccentrics 13 and 1311 are in phase is shown in Figure 7 and the eccentrics act to displace both ends of the rocker member in the same direction by a distance equal to the full throw of each eccentric, and a full stroke is imparted to the plunger 1 and the rocker arm is disposed at right angles to the axis of the plunger and moves between the full line and chain-dotted line positions. When the eccentrics are only partly out of phase and set to intermediate positions the rocker member 10 becomes inclined relatively to its right-angular position (as illustrated by Figure 6) and oscillates about itspivot 11 as shown in chain-dotted outline as the eccentrics rise and fall so that the eccentrics can be said to follow one another with one eccentric subtracting from the movement imparted to the rocker 10 by the other. In other words in intermediate positions the movement of one eccentric is offset by the other with the result that the linear displacement of the pivotal connection 11 of the arm 10 with the plunger 1 is less than when the eccentrics are in phase so that the stroke of the plunger is correspondingly reduced.

In Figures 5 to 7 three main positions of the eccentrics are illustrated which correspond to no stroke (eccentrics 180 out of phase), approximately half stroke (eccentrics out of phase), and full stroke (eccentrics in phase) but it will be appreciated that the eccentrics can be set to an infinite number of in-between positions so that the quantity of fuel pumped by each plunger can be varied to suit requirements.

Figure 8 which, as already stated is an explanatory diagram, indicates the length of the plunger stroke which is dependent upon (a) the angular movement of the setting arm 18 and the number of degrees to which the eccentrics 13 and 13:: are moved out of phase. The table of readings indicated in Figure 8 correspond to the different positions of the eccentrics shown in Figures 5 to 7. In this figure the movement of the arm 18 through the arc A to C at the right hand side of this figure results in the angular displacement of the arm 17 through the arc A to C at the left hand side of this figure. As tabulated, the reading when the outer ends of the arms 18 and 17 are in the A and A positions respectively indicates that the eccentrics are out of phase (Figure 5 position) and no stroke of the piston as indicated in column three. When the arms 18 and 17 have been swung to their B and B positions the arm 18 has been swung through 52.75 and the eccentrics are 90 out of phase and a piston stroke of .180" is obtained (Figure 6). When the arms 18 and 17 are moved to their C and C positions and the arm 18 has been swung through 76 the eccentrics are in phase (Figure 7), Le. 0 giving a piston stroke of .252. This piston stroke of course, varies with the throw of the eccentrics and the readings given are purely examples.

The amount of fuel pumped by each plunger can be adjusted so infinitesimally that the fuel supply to an engine can be regulated with complete accuracy to suit changes in running conditions of the engine.

The setting or adjusting arm 18 can be actuated automatically by the throttle control of an engine, by an engine driven governor or by means which is responsive to engine temperature or by any combination thereof.

To ensure that a constant and sufficient supply of fuel is maintained in the chamber 7, a priming piston 20 (Figures 1 and 3) may be provided in conjunction with each plunger 1, or one which is common to all the plungers, which feeds fuel from the inlet 8 way of a valve 21 to said chamber 7, excess fuel being discharged back to the fuel supply through an outlet 22. The or each priming piston ,20 can be driven by an extension 12b of the strap of an eccentric.

I claim:

1. A phase shifting mechanism for controlling the stroke of a reciprocating element, comprising a driving shaft and a driven shaft mounted in spaced relation, and means for variably regulating the stroke of said element, said means comprising a rocker member medially pivoted to said reciprocating element, an eccentric on the driving shaft, an eccentric on the driven shaft, straps pivoted to the opposite ends of said rocker member, and

' respectively surrounding the periphery of the eccentrics,

a first arm loosely mounted on the driving shaft, a second arm loosely mounted on the driven shaft, a link pivoted at the opposite ends thereof to the free ends of said arms, a train of gearing having the end gears of said train connected with the driving shaft and the driven shaft, the gears intermediate the end gears of the train mounted on said link, and adjusting means for changing the angular position of the rocker member relative to the axis of the reciprocating element, said means having a manually controlled operating portion connected with said first and second arms, whereby, the turning of said operating portion will swing one arm to tilt the link and simultaneously turn the other arm on the drive shaft to cause the rocker member to assume an infinite number of different angular positions.

2. A phase shifting mechanism for a reciprocating piston, comprising, a rocker member pivoted between its ends to said reciprocating member, first and second eccentrics pivotally connected to the ends of said rocker memher, said eccentrics acting on opposite ends of the rocker member to move the latter bodily with said reciprocating member when the eccentrics are wholly or partly in phase, a driving shaft, a driven shaft, a gear train whose end gears are mounted on said shafts, a displaceabi link supporting the intermediate gears of the train, arms free on said driving and driven shafts and pivotally connected to the ends of said link, a manually manipulatable member mounted co-axially with the driven shaft and angularly adjustable to swing said arms whereby, the turning of said operating member will cause one of said arms to tilt the link and simultaneously turn the other arm on the drive shaft to cause the rocker member to assume an infinite number of different angular positions and to move the reciprocating member accordingly.

References Cited in the file of this patent UNITED STATES PATENTS Woydt Sept. 17, 1957 

